Currently I use xmms to play mp3s. When they are stored locally (i.e. on my own hd) they can be opened by double-clicking or dragging them into the xmms window. Yet, most of the mp3s here are on a shared harddisk that I access as a samba-client. When I double-click on such mp3s, xmms merely shows an "open file" dialog-box and refuses to play anything.

I admit this isn't such a big problem, since I can of course manually copy the files I want to play from the network to my hd first. Does someone recognize this behaviour?

Not really... what does "access as a samba client" really mean? You use some kind of smb:// protocol in Konqueror or Nautilus to see the files? xmms does not understand this. What you need to do in that case is to mount the remote samba share locally somewhere so you can touch the files directly.

mkdir /mnt/myshare
mount -t vifs //serverip//sharename /mnt/myshare

should get you started. If you need login credentials, you can give them by appending

Many thanks for your help - wonder if I can cheekily ask for help on the same/almost same problem here?

I have mounted these shares (in /fstab) confirmed working as above - I can play video and sound files from all shares using mplayer / omxplayer and a few others. However, XMMS does play anything at all on any of these shared folders (when accessing through /mnt/myshare etc)

I know there is nothing wrong with XMMS, because I can simply copy a file locally and it plays fine.